Gripper bar



Feb. 7, 1967 1 w L ETAL 3,302,968

GRIPPER BAR 2 Sheets-Sheet 1 Filed Sept. 29, 1965 Feb. 7, 1967 Filed Sept. 29, 1965 L. W. BLEIMAN ETAL GRIPPER BAR 2 Sheets-Sheet 2 wry/my United States Patent 3,302,968 GRIPPER BAR Lewis W. Bleiman, Northridge, and John B. Harrison, Los Angeles, Calif., and Erwin H. Panczner, Villanova, Pa., assignors to Radio Corporation of America, a corporation of Delaware Filed Sept. 29, 1965, Ser. No: 491,226 4 Claims. (Cl. 29487) This invention relates to a new and improved device for gripping a sheet at its edge.

In co-pending application Serial No. 308,012, now Patent No. 3,266,497, filed September 10, 1963, by Lewis W. Bleiman and assigned to the same assignee as the present invention, a mass memory system is described in which information is stored on relatively thin, flexible, plastic sheets (cards) coated with magnetic material. The cards have tabs projecting from their lower and upper edges and are stored in packs in magazines. A card may be selected from a pack by pushing a group of cards including the one desired out of the pack, gripping that one at a tab extending from its exposed edge, and returning the remaining cards to the pack. The se lected card is then moved through an opening in the magazine and into a raceway where the card is propelled toward a read-write station. The gripping and sideways movement of the card is performed by a gripper bar which is discussed generally in the co-pending application above.

An object of the present invention is to provide an improved gripper bar which causes very little bending of the card and thereby greatly increases the life of the card.

The gripper bar of the invention comprises an arrangement of fixed and movable teeth. In one position of the movable teeth, they nest with the fixed teeth and provide a smooth surface configuration to the edge of the card to be gripped. .In a second position of the movable teeth, a flat surface of these teeth is parallel to a corresponding flat surface of the fixed teeth so that when a card is engaged it is held between two relatively large, parallel, fiat surfaces and is not bent appreciably or damaged.

The invention is discussed in greater detail below and is described in the following drawings of which:

FIGURE 1 is a perspective, broken-away view of a prior art gripper bar;

FIGURE 2 is a cross-section through the fixed and movable teeth of the gripper bar of FIGURE 1 showing a card between these teeth;

FIGURE 3 is a perspective, broken-away view of the improved gripper bar of the present invention;

FIGURES 4 and 5 are perspective, broken-away views of the gripper bar of FIGURE 3 showing the teeth in different positions; and

FIGURE 6 is a cross-section along lines 6-6 of FIG- URE 5 and shows also a card in place between a fixed tooth and a movable tooth.

The prior art gripper bar shown in FIGURE 1 includes a fixed support 10 to which are secured a plurality of pairs of fixed teeth 10a and 10b which are equally spaced along the length of the support. Located within the fixed support 10 is a movable support 12 to which are secured a plurality of equidistant teeth 12a. A card is shown in phantom view at 14. The tab of the card 16 is in place between a pair of fixed teeth 10a, 10b and a movable tooth 12a.

The fixed and movable teeth of the arrangement of FIGURE 1 are normally initially positioned with each movable tooth located directly between a pair of fixed teeth. The three teeth together thereby present a smooth profile, on edge. When a card is selected, the tab of the card is moved into the space between the teeth. Then,

Patented Feb. 7, 1967 hoe the support 12 is moved relatively to the support 10 so that the tab is grasped between a pair of fixed teeth and a movable tooth, as shown in FIGURE 2.

While found to be useful and operative, the arrangement of FIGURES 1 and 2 does have the disadvantage that the tab of the card is flexed substantially each time the card is grasped. Moreover, as the card is moved into engagement with the gripper bar at a relatively high velocity and as the teeth of the gripper bar engage the card with a substantial amount of force, the amount of stress placed on the tabs is relatively severe. It is found, in practice, that this bending eventually causes the card tabs to tear or to become damaged. in other respects, in both cases to an extent sufiicient substantially to limit the life of the card.

The improved gripper bar of the present invention is shown in FIGURE 3. In practice, the gripper bar is arranged so that the teeth extend downwardly as shown in FIGURE 1. However, in the interest of ease of illustration, the bar is shown upside down in FIGURE 3. The fixed teeth are mounted on a hollow common supporting structure 20, 20a. Each fixed tooth consists of a back wall 22 with an exposed flat surface and an exposed edge portion 24. Each tooth also includes two side walls 26 and 26a. These side walls are parallel to one another at their inner surfaces and taper at their outer surfaces to relatively narrow exposed edges 28 and 2801, respectively. The front wall and two side walls of each fixed tooth together define an opening of generally rectangular cross-section.

A movable supporting element 30 is located within the channel formed by the supporting means 20, 20a, for the fixed teeth. The movable teeth 32 are located on the movable supporting element 30. These teeth may be integral with the supporting element or may instead be secured thereto. Each movable tooth has a body portion of rectangular cross-section and this body portion is adapted to fit within the hollow formed by the three walls of each fixed tooth. The front surface 34 of each fixed tooth is flat and is parallel to the fiat back surface of the rear wall 22 of each fixed tooth. The end portion 36 of each movable tooth is rounded and overhangs the body portion of the fixed tooth at its rear wall. This overhang, shown at 38, mates with the exposed end 24 of the rear wall of the fixed tooth, when the movable tooth is within the fixed tooth.

The support 20 for the gripper bar is formed with an elongated slot 40. A bar 42, which is secured to the movable support 30, is located in this slot and is movable along the slot. The bar 42 may be connected to a drive element 44, such as a solenoid or the like, for driving the bar and the movable support 30 in the direction of arrows 46.

The normal position for the teeth of the gripper bar is shown in FIGURE 4. Each movable tooth 32 nests with a fixed tooth. The overlapping end portion of the movable tooth slightly projects beyond and covers the edge 24 of the fixed tooth. The tapered ends 28, 28a of the side walls of the fixed tooth abut the respective sides of the fixed tooth. The back surface of the movable tooth also projects a slight amount beyond the corresponding surfaces of the fixed tooth. The overall result is that the nested tooth arrangement provides a smooth surface configuration and cannot easily damage the card if the card should be struck by a nested pair of teeth.

The second position of a pair of teeth of the gripper bar assembly is shown in the cut-away, perspective view of FIGURE 5. Here the flat surface of the back wall 22 of a fixed tooth abuts and is parallel to the corresponding fiat front surface 34 of a movable tooth.

The cross-sectional view of FIGURE 6 shows a card in place between a movable tooth 32 and a fixed tooth 22,

26, 26a. In view of the fiat surface-to-flat surface engagement with the card, there is very little bending of the card. It is found, in practice, that with the present gripper bar assembly the life of the cards is extended to several tens of thousands of selection cycles.

While for purposes of the present arrangement only one gripper bar is shown, it is to be appreciated that, in practice, more than one may be employed. For example, a plurality of bars may be arranged as shown in FIGURE 7b of the co-pending application. As a third alternative, a group such as four pairs of bars may be arranged sideby-side. These bars may be movable to one of two different positions for selecting one card in eight. In a preferred method of operation, three of the bars are maintained a suflicient distance from the cards when the group of cards is moved up out of the pack so that none of these cards strike the three bars. The fourth bar is moved downwardly and grips the one card in eight it is desired to select.

What is claimed is:

1. A device for gripping a sheet at its edge comprising, in combination:

a plurality of aligned, equally spaced, first elements fixed to a common support, each element having a first fiat surface and an opposite surface;

a plurality of aligned, equally spaced, second elements fixed to a common support which is movable with respect to the support for the first elements, each second element having a flat surface which is parallel to and faces the first surface of the first element, and an end portion which is rounded and overlaps the exposed free end of a first element when the second element is adjacent to said opposite surface of a first element, and

means for moving the second elements relatively to the first elements from a position at which their end portions respectively overlap the free ends of the first element to a position such that the respective flat surfaces of the second elements are parallel to and abut the respective fiat surfaces of the first elements.

2. A device for gripping a sheet at its edge comprising, in combination:

a plurality of aligned first elements fixed to a common support, each having a rear wall with an exposed flat surface and two side walls;

a plurality of aligned second elements fixed to a common support which is movable with respect to the support for the first elements, each second element having a body portion which fits into the space defined by the three walls of the first element, a fiat front surface which is exposed and is parallel to the flat surface of the rear wall of the first element, and an end portion which is rounded and fits over the exposed end of the rear wall of a first element when the second element is within a first element; and

means for moving the second elements relatively to the first elements from a position within the first elements to a position such that the respective fiat surfaces of the front walls of the second elements are parallel to and abut the fiat surfaces of the rear walls of the first elements.

3. A device as set forth in claim 2 wherein the side walls of the first elements are tapered to narrow, exposed free ends so that when the second elements are in place within the first elements the narrow free ends of the side walls of the first elements abut the respective sides of the second elements.

4. A device as set forth in claim 3 wherein the common support for the first elements is formed with a longitudinal channel and the common support for the second elements is located in said channel;

References Cited by the Examiner UNITED STATES PATENTS 11/1950 Schneider 294-87 3/ 1953 Pizzani 294-87 

1. A DEVICE FOR GRIPPING A SHEET AT ITS EDGE COMPRISING, IN COMBINATION: A PLURALITY OF ALIGNED, EQUALLY SPACED, FIRST ELEMENTS FIXED TO A COMMON SUPPORT, EACH ELEMENT HAVING A FIRST FLAT SURFACE AND AN OPPOSITE SURFACE; A PLURALITY OF ALIGNED, EQUALLY SPACED, SECOND ELEMENTS FIXED TO A COMMON SUPPORT WHICH IS MOVABLE WITH RESPECT TO THE SUPPORT FOR THE FIRST ELEMENTS, EACH SECOND ELEMENT HAVING A FLAT SURFACE WHICH IS PARALLEL TO AND FACES THE FIRST SURFACE OF THE FIRST ELEMENT, AND AN END PORTION WHICH IS ROUNDED AND OVERLAPS THE EXPOSED FREE END OF A FIRST ELEMENT WHEN THE SECOND ELEMENT IS ADJACENT TO SAID OPPOSITE SURFACE OF A FIRST ELEMENT; AND MEANS FOR MOVING THE SECOND ELEMENTS RELATIVELY TO THE FIRST ELEMENT FROM A POSITION AT WHICH THEIR END PORTIONS RESPECTIVELY OVERLAP THE FREE ENDS OF THE FIRST ELEMENT TO A POSITION SUCH THAT THE RESPECTIVE FLAT SURFACES OF THE SECOND ELEMENTS ARE PARALLEL TO AND ABUT THE RESPECTIVE FLAT SURFACES OF THE FIRST ELEMENTS. 